Long-term Survival after Surgery for Acute Coronary Syndromes in Relation to Perioperative Troponin T Release and Angina Class – A Prospective Study in 200 Patients

Abstract

Patients with acute coronary syndrome have an increased risk of cardiac death or myocardial infarction after urgent coronary artery bypass surgery (CABG). Symptoms and signs of ongoing ischemia, such as elevated cardiac troponin T and angina at rest at the time of the operation identify patients at particular risk of early death, but the impact of these parameters on long-term survival is poorly investigated. Two hundred patients, 100 with acute coronary syndrome and 100 with stable angina pectoris, underwent primary isolated CABG. Troponin T levels were assayed immediately before the operation and at 64 hours after the aortic cross-clamp had been removed. The severity of the patients' unstable symptoms was classified according to Braunwald. Early outcome and long-term survival were analyzed. Among the unstable patients 3 deaths occurred within 30 days of the operation, and there were 12 late deaths. In the control group there were no early and 19 late deaths. The patients were followed up for 6.5 years (0-7.7 years), a total of 1 294 patient years. The cumulative long-term survival was 85 % for the unstable and 81 % for the stable patients ( P = 0.75). Freedom from cardiac death was 92 % in unstable and 94 % in stable patients. Five unstable and one of the stable patients suffered postoperative myocardial infarction ( P = 0.01). A troponin T level > 0.1 microg/L immediately prior to the operation was associated with an increased need for postoperative pharmacological inotropic support ( P < 0.001) and intra-aortic balloon counterpulsation ( P = 0.004). Symptoms and signs of ongoing ischemia (angina at rest and elevated troponin T immediately prior to the operation) had no predictive value for long-term survival. In patients with acute coronary syndrome, parameters such as elevated troponin T and angina at rest herald an increased risk of postoperative myocardial infarction and indicate the need for pharmacological and mechanical inotropic support but have no bearing on long-term survival.